Magnetic latch



June 24, 1958 H. Q, SCOTT ET AL 2,840,48

MAGNETIC LATCH Filed May 24, 1956 A TTOP/VIVS United States Patent OMAGNETIC LATCH Hayes 0. Scott and Raymond L. Pietsch, Flint, Mich., as-

sig'nors to The Engineered Products Company, Flint, Mich., a corporationof Michigan Application May 24, 1956, Serial No. 587,020

11 Claims. (Cl. 292-2515) This invention relates to a magnetic latch andmore particularly to a bore-in type of latch for holding sliding doorsin closed position.

It is an object of this invention to provide a latch of the typedescribed wherein the magnet assembly is oatingly mounted on a faceplate so that full contact with the strike is assured.

further object of the invention resides in the provision of a magneticbore-in latch wherein a Boating connection between themagnet assemblyand the face plate of the latch is designed for economic-a1 manufacture.

ln the drawings: Fig. 1 is a fragmentary side elevational view of aslidmg door panel provided with the magnetic latch of the presentinvention.

Fig. 2 is a fragmentary vertical sectional View of the latch with thedoor in the fully closed position.

Fig. 3 is a fragmentary end View of the door panel showing the latchmounted thereon.

Fig. 4 is a fragmentary sectional view of an enlarged scale showing thelloating connection between the magnet assembly and the face plate. f' vReferring more particularly to the drawings, there 1s shown in Fig. 1 adoor panel 10 mounted for sliding movement in a frame member 12 providedwith a jamb 14. The end face 16 of the door has the magnetic latch 18mounted therein; and on the jamb 14, there is arranged a strike plate 20adapted to be engaged by latch 18. The particular construction of thelatch of the present invention is illustrated in Fig. 2. The latchincludes a rectangular face plate 22 formed of brass or othernon-magnetic material and a magnet assembly 24 mounted on face plate 22in a manner described hereinafter. Door panel is provided with amortised recess 26 in which face plate 22 is adapted to be secured bymeans of mounting screws 28. The magnet assembly 24 is received within acylindrical socket 30 bored in the end face 16 of the door.

Magnet assembly 24 comprises an outer cylindrical sleeve 32 preferablyfashioned from steel tubing. Within sleeve 32, there is arranged anon-magnetic liner 34 which is advantageously formed from a piece ofbrass tubing. Within liner 34, there is arranged a cylindrical barmagnet 36. At the inner end of magnet assembly 24, an end plug 33 formedof steel or other magnetic material is pressed fitted into the end ofsteel sleeve 32. The inner end of magnet 36 abuts against the inner faceof end plug 3i; so that the end plug 33 forms a nx path between magnet36 and sleeve 32. At the outer end of magnet assembly 24, an end plug 40is press fitted into the end of brass liner 34 in abutting relation withthe outer end of magnet 36. The press ts of end plugs 33 and 40 insurean integral connection between the various elements of the magnetassembly 24. In this arrangement, it will be observed that sleeve 32 andend plug 40 form the pole pieces of the assembly and these pole piecesare Patented June 24, 1958 ICC 2 insulated magnetically from one anotherby the brass liner 34.

In magnets of this type for sliding doors, the door is effectively heldin the closed position only when the pole pieces of the magnet are incomplete face-to-face contact with the strike plate 20. Strike plate 20may be in the form of a circular disc mounted on the jamb 14 as by amounting screw 42. When a magnet assembly such as shown at 24 is rigidlymounted on a face plate such as that shown at 22, misalignment of eitherthe door or the latch itself results in only partial contact of themagnet assembly with strike plate 20. Thus, as a practical matter, it isdesirable to mount the magnet assembly 24 in a floating condition onface plate 22. v

In the latch of the present invention, this floating connection iseffected very economically in a manner illustrate'd in Figs. 2 and 4.Outer sleeve 32 has an annular groove 44 formed around the outer surfacethereof adjacent its outer end. The width of groove 44 is substantiallygreater than the thickness of the material from which face plate 22 isfashioned. Face plate 22 is formed with a central opening 46, and theportion 48 of face plate 22 surrounding opening 46 is originally formedin a flared condition so that the magnet assembly 24 can be insertedthrough the opening 46. Thereafter, the portion 48 of Vface plate 22 iscrimped to bring the edge 50 surrounding opening 46 into the undercutannular groove v44 in outer sleeve 32.

In the assembled condition of the latch, the diameter of central opening46 is slightly greater than the diameter of the undercut groove 44. Aspointed out previously, groove 44 is also Wider than the thickness ofthe portion 48 of face plate 22. Thus, the magnet assembly 24 is free toshift slightly axially with respect toface plate 22 and at the same timeis permitted a slight amount of universal pivoting movement on faceplate 22. It follows, therefore, that if there should be some slightmisalignment between the plane of face plate 22 and Vthe plane of strikeplate 20, the iloating connection between magnet assembly 24 and faceplate 22 will compensate for this misalignment; and when the door isclosed, the pole piece 40 will automatically engage strike plate 2t) infull face-to-face contact, thus utilizing the maximum magneticattracting power of magnet 36 to effectively hold the sliding door 10 inclosed position. It will be obvious that the oating connection describedherein lends itself admirably to economical production manufacture.

We claim:

1. A magnetic bore-in latch for sliding doors including a face plateadapted to be mounted on the edge of the sliding door and a magnetassembly supported on said face plate and projecting therethrough, saidmagnet assembly including an outer cylindrical sleeve having an annulargroove around the outer face thereof closely adjacent but spacedfrom-the end of saidr magnet assembly projecting through said faceplate, said face plate having an opening therein through which saidmagnet assembly projects, the portion of said face plate surroundingsaid opening being disposed within said annular groove to iloatinglymount said magnet assembly on said face plate.

2. A magnetic bore-in latch for sliding doors including a face platehaving a central opening therein with the portion thereof surroundingsaid opening being flared inwardly of the outer face of said face plate,a magnet assembly projecting through said central opening, said magnetassembly being generally cylindrically shaped at the portion thereofprojecting through said face plate and having an annular groove aroundthe outer surface thereof spaced from the adjacent end of the magnet,said inwardly ared portion of said face plate being disposed.

withinsaid annular grooveto oatingly net assembly on-said face plate. t

3. A magnetic bore-in lateh as called for in claim 2 wherein the widthof said gr'ove is substantially greater than th'e-tthiokn'est.` of said"face' plate Vat said` inwardly ared portion thereof. p

4;1nag`netic bore-in latch asv-called for in claim 3 wherein thediameter o'f said central aperture in the face plate is greater than theouter diameter of the base of said annular groove;

5. Amagnetic bore-in latch as called orvin claim 4- wherein said magnetassembly projects through said in Wardly ed? portion of said face plateto at least the plane `ofl said face plate.

6. Ama'gneticbore-inlatch for sliding doorsl comprising a face platehaving a-centralaperture, the portion of said `faceplate surroundingsaid central aperture being ared inwardly fromthe` outerface of the faceplate, a magnet assembly projecting through said central aperture,saidimagnet assembly including a cylindrical tube formed of magneticmaterial and a `magnet insulatively supported Within and extendingaxially of said Atube', means forming a tlux path between said tube andone end of the magnet, said tube having a circumferential groove aroundtheouter surface thereof at the portion projecting through said inwardlyflared portion of the face plate, said groove being spaced slightly fromthe adjacent end of the tube, said inwardly flared portion of said faceplate being loosely retained in said groove.

mount the mag- 7. A magnetic bore-in latch as called for in claim 6wherein said means comprises a plug formed of magnetic material pressfitted into the inner end of said tube and abutting the inner end ofsaid magnet.

8. A magnetic bore-in latch as called for in claim 7 including a linerformed of non-magnetic material disposed between said magnet and theinner face of said tube.

9. A magnetic bore-in latch as called for in claim 8 including a plugformed of magnetic material press tted into the outer end of said linerand abutting against the outer end of said magnet, said last-mentionedplug and said tube forming concentrically disposed pole pieces.

l0. A magnetic bore-in latch as called for in claim 9 wherein thediameter of said groove at the base thereof is slightly less than thediameter of said central aperture.

1l. A magnetic bore-in latch as called for in claim 10 wherein the widthof said groove is substantially greater than the thickness of said faceplate at said inwardly flared portion thereof.

References Cited in the lle of this patent UNITED STATES PATENTS'2,240,035 Catherall Apr. 29, 1941 FOREIGN PATENTS 814,855 Germany Oct.29, 1951

